/*  _______         ____    __         ___    ___
 * \    _  \       \    /  \  /       \   \  /   /       '   '  '
 *  |  | \  \       |  |    ||         |   \/   |         .      .
 *  |  |  |  |      |  |    ||         ||\  /|  |
 *  |  |  |  |      |  |    ||         || \/ |  |         '  '  '
 *  |  |  |  |      |  |    ||         ||    |  |         .      .
 *  |  |_/  /        \  \__//          ||    |  |
 * /_______/ynamic    \____/niversal  /__\  /____\usic   /|  .  . ibliotheque
 *                                                      /  \
 *                                                     / .  \
 * readptm.c - Code to read a Poly Tracker v2.03      / / \  \
 *             module from an open file.             | <  /   \_
 *                                                   |  \/ /\   /
 * By Christopher Snowhill. Based on reads3m.c        \_  /  > /
 * by entheh.                                           | \ / /
 *                                                      |  ' /
 *                                                       \__/
 */

// IT_STEREO... :o
#include <stdlib.h>
#include <string.h>

#include "dumb.h"
#include "internal/it.h"

static int it_ptm_read_sample_header(IT_SAMPLE *sample, long *offset,
                                     DUMBFILE *f) {
    int flags;

    flags = dumbfile_getc(f);

    dumbfile_getnc((char *)sample->filename, 12, f);
    sample->filename[12] = 0;

    sample->default_volume = dumbfile_getc(f);

    sample->C5_speed = dumbfile_igetw(f) << 1;

    dumbfile_skip(f, 2); /* segment */

    *offset = dumbfile_igetl(f);

    sample->length = dumbfile_igetl(f);
    sample->loop_start = dumbfile_igetl(f);
    sample->loop_end = dumbfile_igetl(f);

    /* GUSBegin, GUSLStart, GUSLEnd, GUSLoop, reserverd */
    dumbfile_skip(f, 4 + 4 + 4 + 1 + 1);

    dumbfile_getnc((char *)sample->name, 28, f);
    sample->name[28] = 0;

    /*
    if (dumbfile_mgetl(f) != DUMB_ID('P','T','M','S'))
            return -1;
    */

    /* BLAH! Shit likes to have broken or missing sample IDs */
    dumbfile_skip(f, 4);

    if ((flags & 3) == 0) {
        /* Looks like no sample */
        sample->flags &= ~IT_SAMPLE_EXISTS;
        return dumbfile_error(f);
    }

    sample->global_volume = 64;

    sample->flags = IT_SAMPLE_EXISTS;
    if (flags & 4)
        sample->flags |= IT_SAMPLE_LOOP;
    if (flags & 8)
        sample->flags |= IT_SAMPLE_PINGPONG_LOOP;

    if (flags & 16) {
        sample->flags |= IT_SAMPLE_16BIT;

        sample->length >>= 1;
        sample->loop_start >>= 1;
        sample->loop_end >>= 1;
    }

    if (sample->loop_end)
        sample->loop_end--;

    sample->default_pan = 0; // 0 = don't use, or 160 = centre?

    if (sample->length <= 0)
        sample->flags &= ~IT_SAMPLE_EXISTS;
    else if (sample->flags & IT_SAMPLE_LOOP) {
        if ((unsigned int)sample->loop_end > (unsigned int)sample->length)
            sample->flags &= ~IT_SAMPLE_LOOP;
        else if ((unsigned int)sample->loop_start >=
                 (unsigned int)sample->loop_end)
            sample->flags &= ~IT_SAMPLE_LOOP;
        else
            sample->length = sample->loop_end;
    }

    // Do we need to set all these?
    sample->vibrato_speed = 0;
    sample->vibrato_depth = 0;
    sample->vibrato_rate = 0;
    sample->vibrato_waveform = IT_VIBRATO_SINE;
    sample->finetune = 0;
    sample->max_resampling_quality = -1;

    return dumbfile_error(f);
}

static int it_ptm_read_byte(DUMBFILE *f) {
    int meh = dumbfile_getc(f);
    if (meh < 0)
        return 0;
    return meh;
}

static int it_ptm_read_sample_data(IT_SAMPLE *sample, int last, DUMBFILE *f) {
    long n;
    int s;

    sample->data =
        malloc(sample->length * (sample->flags & IT_SAMPLE_16BIT ? 2 : 1));
    if (!sample->data)
        return -1;

    s = 0;

    if (sample->flags & IT_SAMPLE_16BIT) {
        unsigned char a, b;
        for (n = 0; n < sample->length; n++) {
            a = s += (signed char)it_ptm_read_byte(f);
            b = s += (signed char)it_ptm_read_byte(f);
            ((short *)sample->data)[n] = a | (b << 8);
        }
    } else {
        for (n = 0; n < sample->length; n++) {
            s += (signed char)it_ptm_read_byte(f);
            ((signed char *)sample->data)[n] = s;
        }
    }

    if (dumbfile_error(f) && !last)
        return -1;

    return 0;
}

static int it_ptm_read_pattern(IT_PATTERN *pattern, DUMBFILE *f,
                               unsigned char *buffer, size_t length) {
    int buflen = 0;
    int bufpos = 0;
    int effect, effectvalue;

    IT_ENTRY *entry;

    unsigned char channel;

    if (!length)
        return -1;

    pattern->n_rows = 0;
    pattern->n_entries = 0;

    /* Read in the pattern data, little by little, and work out how many
     * entries we need room for. Sorry, but this is just so funny...
     */
    for (;;) {
        unsigned char b = buffer[buflen++] = dumbfile_getc(f);

#if 1
        static const unsigned char used[8] = {0, 2, 2, 4, 1, 3, 3, 5};
        channel = b & 31;
        b >>= 5;
        pattern->n_entries++;
        if (b) {
            if (buflen + used[b] >= 65536)
                return -1;
            dumbfile_getnc((char *)buffer + buflen, used[b], f);
            buflen += used[b];
        } else {
            /* End of row */
            if (++pattern->n_rows == 64)
                break;
            if (buflen >= 65536)
                return -1;
        }
#else
        if (b == 0) {
            /* End of row */
            pattern->n_entries++;
            if (++pattern->n_rows == 64)
                break;
            if (buflen >= 65536)
                return -1;
        } else {
            static const unsigned char used[8] = {0, 2, 2, 4, 1, 3, 3, 5};
            channel = b & 31;
            b >>= 5;
            if (b) {
                pattern->n_entries++;
                if (buflen + used[b] >= 65536)
                    return -1;
                dumbfile_getnc(buffer + buflen, used[b], f);
                buflen += used[b];
            }
        }
#endif

        /* We have ensured that buflen < 65536 at this point, so it is safe
         * to iterate and read at least one more byte without checking.
         * However, now would be a good time to check for errors reading from
         * the file.
         */

        if (dumbfile_error(f))
            return -1;

        /* Great. We ran out of data, but there should be data for more rows.
         * Fill the rest with null data...
         */
        if (buflen >= (dumb_ssize_t)length && pattern->n_rows < 64) {
            while (pattern->n_rows < 64) {
                if (buflen >= 65536)
                    return -1;
                buffer[buflen++] = 0;
                pattern->n_entries++;
                pattern->n_rows++;
            }
            break;
        }
    }

    pattern->entry = malloc(pattern->n_entries * sizeof(*pattern->entry));

    if (!pattern->entry)
        return -1;

    entry = pattern->entry;

    while (bufpos < buflen) {
        unsigned char b = buffer[bufpos++];

        if (b == 0) {
            /* End of row */
            IT_SET_END_ROW(entry);
            entry++;
            continue;
        }

        channel = b & 31;

        if (b & 224) {
            entry->mask = 0;
            entry->channel = channel;

            if (b & 32) {
                unsigned char n = buffer[bufpos++];
                if (n == 254 || (n >= 1 && n <= 120)) {
                    if (n == 254)
                        entry->note = IT_NOTE_CUT;
                    else
                        entry->note = n - 1;
                    entry->mask |= IT_ENTRY_NOTE;
                }

                entry->instrument = buffer[bufpos++];
                if (entry->instrument)
                    entry->mask |= IT_ENTRY_INSTRUMENT;
            }

            if (b & 64) {
                effect = buffer[bufpos++];
                effectvalue = buffer[bufpos++];
                _dumb_it_ptm_convert_effect(effect, effectvalue, entry);
            }

            if (b & 128) {
                entry->volpan = buffer[bufpos++];
                if (entry->volpan <= 64)
                    entry->mask |= IT_ENTRY_VOLPAN;
            }

            entry++;
        }
    }

    ASSERT(entry == pattern->entry + pattern->n_entries);

    return 0;
}

/** WARNING: this is duplicated in itread.c - also bad practice to use the same
 * struct name unless they are unified in a header */
/* Currently we assume the sample data are stored after the sample headers in
 * module files. This assumption may be unjustified; let me know if you have
 * trouble.
 */

#define PTM_COMPONENT_INSTRUMENT 1
#define PTM_COMPONENT_PATTERN 2
#define PTM_COMPONENT_SAMPLE 3

typedef struct PTM_COMPONENT {
    unsigned char type;
    unsigned char n;
    long offset;
} PTM_COMPONENT;

static int ptm_component_compare(const void *e1, const void *e2) {
    return (int)(((const PTM_COMPONENT *)e1)->offset -
                 ((const PTM_COMPONENT *)e2)->offset);
}

static DUMB_IT_SIGDATA *it_ptm_load_sigdata(DUMBFILE *f) {
    DUMB_IT_SIGDATA *sigdata;

    PTM_COMPONENT *component;
    int n_components = 0;

    int n;

    unsigned char *buffer;

    sigdata = malloc(sizeof(*sigdata));
    if (!sigdata)
        return NULL;

    /* Skip song name. */
    dumbfile_getnc((char *)sigdata->name, 28, f);
    sigdata->name[28] = 0;

    if (dumbfile_getc(f) != 0x1A || dumbfile_igetw(f) != 0x203) {
        free(sigdata);
        return NULL;
    }

    dumbfile_skip(f, 1);

    sigdata->song_message = NULL;
    sigdata->order = NULL;
    sigdata->instrument = NULL;
    sigdata->sample = NULL;
    sigdata->pattern = NULL;
    sigdata->midi = NULL;
    sigdata->checkpoint = NULL;

    sigdata->n_orders = dumbfile_igetw(f);
    sigdata->n_instruments = 0;
    sigdata->n_samples = dumbfile_igetw(f);
    sigdata->n_patterns = dumbfile_igetw(f);

    if (dumbfile_error(f) || sigdata->n_orders <= 0 ||
        sigdata->n_orders > 1024 || // Whoa, nelly.
        sigdata->n_samples > 255 || sigdata->n_patterns > 128) {
        _dumb_it_unload_sigdata(sigdata);
        return NULL;
    }

    sigdata->n_pchannels = dumbfile_igetw(f);

    if (dumbfile_igetw(f) != 0) {
        _dumb_it_unload_sigdata(sigdata);
        return NULL;
    }

    dumbfile_skip(f, 2);

    if (dumbfile_mgetl(f) != DUMB_ID('P', 'T', 'M', 'F')) {
        _dumb_it_unload_sigdata(sigdata);
        return NULL;
    }

    dumbfile_skip(f, 16);

    sigdata->order = malloc(sigdata->n_orders);
    if (!sigdata->order) {
        _dumb_it_unload_sigdata(sigdata);
        return NULL;
    }

    if (sigdata->n_samples) {
        sigdata->sample = malloc(sigdata->n_samples * sizeof(*sigdata->sample));
        if (!sigdata->sample) {
            _dumb_it_unload_sigdata(sigdata);
            return NULL;
        }
        for (n = 0; n < sigdata->n_samples; n++)
            sigdata->sample[n].data = NULL;
    }

    if (sigdata->n_patterns) {
        sigdata->pattern =
            malloc(sigdata->n_patterns * sizeof(*sigdata->pattern));
        if (!sigdata->pattern) {
            _dumb_it_unload_sigdata(sigdata);
            return NULL;
        }
        for (n = 0; n < sigdata->n_patterns; n++)
            sigdata->pattern[n].entry = NULL;
    }

    /** WARNING: which ones? */
    sigdata->flags =
        IT_STEREO | IT_OLD_EFFECTS | IT_COMPATIBLE_GXX | IT_WAS_A_PTM;

    sigdata->global_volume = 128;
    sigdata->speed = 6;
    sigdata->tempo = 125;
    sigdata->mixing_volume = 48;

    /* Panning positions for 32 channels */
    {
        int i;
        for (i = 0; i < 32; i++) {
            int c = dumbfile_getc(f);
            if (c <= 15) {
                sigdata->channel_volume[i] = 64;
                sigdata->channel_pan[i] = c;
            } else {
                /** WARNING: this could be improved if we support channel
                 * muting... */
                sigdata->channel_volume[i] = 0;
                sigdata->channel_pan[i] = 7;
            }
        }
    }

    /* Orders, byte each, length = sigdata->n_orders (should be even) */
    dumbfile_getnc((char *)sigdata->order, sigdata->n_orders, f);
    sigdata->restart_position = 0;

    component = malloc(768 * sizeof(*component));
    if (!component) {
        _dumb_it_unload_sigdata(sigdata);
        return NULL;
    }

    if (dumbfile_seek(f, 352, DFS_SEEK_SET)) {
        free(component);
        _dumb_it_unload_sigdata(sigdata);
        return NULL;
    }

    for (n = 0; n < sigdata->n_patterns; n++) {
        component[n_components].type = PTM_COMPONENT_PATTERN;
        component[n_components].n = n;
        component[n_components].offset = dumbfile_igetw(f) << 4;
        n_components++;
    }

    if (dumbfile_seek(f, 608, DFS_SEEK_SET)) {
        free(component);
        _dumb_it_unload_sigdata(sigdata);
        return NULL;
    }

    for (n = 0; n < sigdata->n_samples; n++) {
        if (it_ptm_read_sample_header(&sigdata->sample[n],
                                      &component[n_components].offset, f)) {
            free(component);
            _dumb_it_unload_sigdata(sigdata);
            return NULL;
        }
        if (!(sigdata->sample[n].flags & IT_SAMPLE_EXISTS))
            continue;
        component[n_components].type = PTM_COMPONENT_SAMPLE;
        component[n_components].n = n;
        n_components++;
    }

    qsort(component, n_components, sizeof(PTM_COMPONENT),
          &ptm_component_compare);

    {
        int i;
        for (i = 0; i < 32; i++) {
            sigdata->channel_pan[i] -= (sigdata->channel_pan[i] & 8) >> 3;
            sigdata->channel_pan[i] = ((int)sigdata->channel_pan[i] << 5) / 7;
            if (sigdata->channel_pan[i] > 64)
                sigdata->channel_pan[i] = 64;
        }
    }

    sigdata->pan_separation = 128;

    if (dumbfile_error(f)) {
        free(component);
        _dumb_it_unload_sigdata(sigdata);
        return NULL;
    }

    buffer = malloc(65536);
    if (!buffer) {
        free(component);
        _dumb_it_unload_sigdata(sigdata);
        return NULL;
    }

    for (n = 0; n < n_components; n++) {
        if (dumbfile_seek(f, component[n].offset, DFS_SEEK_SET)) {
            free(buffer);
            free(component);
            _dumb_it_unload_sigdata(sigdata);
            return NULL;
        }

        switch (component[n].type) {

        case PTM_COMPONENT_PATTERN:
            if (it_ptm_read_pattern(
                    &sigdata->pattern[component[n].n], f, buffer,
                    (n + 1 < n_components)
                        ? (component[n + 1].offset - component[n].offset)
                        : 0)) {
                free(buffer);
                free(component);
                _dumb_it_unload_sigdata(sigdata);
                return NULL;
            }
            break;

        case PTM_COMPONENT_SAMPLE:
            if (it_ptm_read_sample_data(&sigdata->sample[component[n].n],
                                        (n + 1 == n_components), f)) {
                free(buffer);
                free(component);
                _dumb_it_unload_sigdata(sigdata);
                return NULL;
            }
        }
    }

    free(buffer);
    free(component);

    if (_dumb_it_fix_invalid_orders(sigdata) < 0) {
        _dumb_it_unload_sigdata(sigdata);
        return NULL;
    }

    return sigdata;
}

DUH *dumb_read_ptm_quick(DUMBFILE *f) {
    sigdata_t *sigdata;

    DUH_SIGTYPE_DESC *descptr = &_dumb_sigtype_it;

    sigdata = it_ptm_load_sigdata(f);

    if (!sigdata)
        return NULL;

    {
        const char *tag[2][2];
        tag[0][0] = "TITLE";
        tag[0][1] = (const char *)(((DUMB_IT_SIGDATA *)sigdata)->name);
        tag[1][0] = "FORMAT";
        tag[1][1] = "PTM";
        return make_duh(-1, 2, (const char *const(*)[2])tag, 1, &descptr,
                        &sigdata);
    }
}
